Various oil and gas well operations will benefit from a suitable system allowing rapid deployment of temporary equipment to allow rapid and efficient removal of liquids and entrained solids from a wellbore. Preferably, such a system further provides a method for removing solids, for example sand or formation fines, which block the wellbore. In one application, it may be desirable to remove a fixed quantity of wellbore fluid to reestablish flow in a gas well.
A common technique used to remove wellbore fluid from a wellbore includes running conventional coiled tubing into the well and pumping compressed air or nitrogen gas into the wellbore to gas lift the fluid to surface. This approaches may overpressure the wellbore, pushing at least a portion of the wellbore fluid back into the formation (as opposed to being pumped to the surface). Furthermore, nitrogen gas is costly, while use of compressed air carries safety concerns.
Following fracturing of a well, it may be desirable to have available a rapidly-deployable temporary system to remove fracture treatment fluid from the well. Preferably, the system would is capable of reporting real-time data pertaining to conditions such as flowing bottomhole pressure and temperature. The data facilitates assessment of reservoir characteristics and determination of optimal permanent production and pumping equipment. Without installing permanent pumping equipment, the options to accomplish the above are otherwise limited.
Jet pumps are useful in a wide range of well applications. Nonetheless, jet pumps for use in hydrocarbon recovery are a relatively underdeveloped technology.
U.S. Pat. No. 5,372,190 discloses a downhole jet pump useful with various types of wells, including gas wells which produce a large ratio of water and may include considerable abrasive solid materials. The downhole jet pump can be run and retrieved inside coil tubing, or conventional threaded pipe, of relatively small diameters. The embodiments of the jet pump disclosed enable removal, replacement or adjustment to provide optimum operation of the pump in accordance with installation requirements without the use of special tools.
To date, jet pump systems have been installed using either conventional jointed tubing or conventional coiled tubing. In some of these installations, the process requires that there be two strings installed in the well. Where two strings are used, they are most typically configured as a tubing string inside of a tubing string, or a concentric configuration. In most of these applications the tubing systems are not adapted for rapid deployment and retrieval.
U.S. Pat. No. 5,033,545 discloses a jet pump that brings a power fluid to sedimented solids and the like plugging a conduit, and includes at least one nozzle which directs the power fluid in a high-velocity jet against the solids to bring the solids into suspension for subsequent removal thereof using the jet pump principle.
There are operational and technical advantages to configuring the system with two or more parallel tubing strings or electrical conductors. However, until recently significant practical problems with this approach had not been addressed. The present invention provides a jet pump which is readily deployed and installed in a wellbore using a single conventional coiled tubing unit. Combining the jet pump with a spoolable multi-string tubing system facilitates a broad range of applications.
It is, therefore, desirable to provide a system and method for jet pump and multi-string tubing for well clean out and testing.